Greetings!

When your car is cranking over and is not starting, We will have to pinpoint what the engine is missing.


Spark


Fuel


Compression



All three of these are tested when the engine is being cranked over. There are two way of checking for fuel. Fuel pressure and fuel trigger. Both are very important and must be present for the engine to start. Fuel pressure is self explanatory. You just hook up the gage and see what the reading is. Fuel trigger is check with a noid light. The injector gets unplugged and the noid light gets plugged in to the injector clip. With the engine cranking over, this light must blink. This is the signal to the injectors from the computer. You can have all the fuel pressure in the world, but it wont matter if the injector is not pulsing gas into the cylinder like it should! Compression tester, spark tester, fuel pressure gage and noid light are all accessible at your local auto store. All three tests play a very important part in diagnosing a no start condition. Be extremely careful when doing these tests.

If in fact it is getting too much fuel, it could be one of two things.

Either the coolant temp sensor is bad causing the computer to give way to much fuel to the cylinders through the injectors upon start up. Or gas is leaking past one or more of the injectors into the cylinders. This could be caused by a few things. But we would need to verify this. TO do this, we need to check fuel pressure. WIth the fuel pressure gage hooked up, we need to turn the key on the prime fuel system. Watch the fuel gage and make sure the fuel pressure does not leak down. If it does, something is leaking.

Also, for grins, be sure to check the fuel pressure regulator. It is located on the fuel rail. It is round, about a quarter size and has a vacuum line going to it. If the regulator is leaking gas than it can cause this problem. Pull off the vacuum line that goes to the regulator. Be absolutely sure there is no gas in the vacuum line. If there is, the diaphragm has ruptured and there is gas entering the engine that is not accounted for and the regulator will need to be replaced!

SOrry for the delay!

The fuel pressure should hold for several hours. If it leaks down within 10 minutes or less, something is leaking.

If it is leaking down, and the regulator is not leaking, then the only thing it could be is the fuel pump or the injectors.

If fuel pressure is not leaking down and the motor is in fact getting way to much fuel on start up, then we need to look at the computer inputs like coolant temp sensor, map or mass air flow sensor and tps sensor.

Let me know!

Located at the side of intake manifold, this sensor measures the temperature of the engine coolant and converts its change into that in resistance through the thermistor.
By monitoring the resistance of the coolant temperature sensor, ECM detects the engine coolant temperature and that affects most systems under the control of ECM.

 

 

 

Here are the specs.

 

177 ohms at 212 deg F
241 ohms at 194 deg F
332 ohms at 176 deg F
467 ohms at 158 deg F
667 ohms at 140 deg F
973 ohms at 122 deg F
1459 ohms at 104 deg F
2238 ohms at 86 deg F
3520 ohms at 68 deg F
5670 ohms at 50 deg F
9420 ohms at 32 deg F
16180 ohms at -14 deg F
28680 ohms at -4 deg F
52700 ohms at -22 deg F
100700 ohms at -40 deg F